Analgesic: Pain relief medication.

Arthralgia: Pain in the joints.

Arthritis: Inflammation of the joints. There are more than 100 kinds of arthritis.

Autoimmune: A process by which a person's immune system attacks the body's own tissues. Rheumatoid arthritis is an autoimmune disease.

Bacteria: Microscopic, one-celled organisms.

Cartilage: Firm, whitish substance at the ends of bones. It acts as the body's "shock absorbers."

Collagen: Substance making up the body's connective tissues.  It gives cartilage its "bounce."

Corticosteroid: Powerful steroid medication that reduces inflammation.

Glucosamine: An amino sugar occurring in vertebrate tissues including that of marine creatures, from which it's harvested.

Glucosamine sulfate: A form of glucosamine that has been shown to reduce arthritis pain and rebuild damaged joints.

Gout: A painful inflammation primarily of the big toe, characterized by an excess of uric acid in the blood that leads to crystalline deposits in the small joints.

Ligament: A band of strong connective tissue that connects bones and holds organs in place.

Osteoarthritis: A type of arthritis in which cartilage wears out and joints become stiff and painful.

Prostaglandins: Hormone-like substances that play a part in inflammation.

Proteoglycans: Mortar-like substances made from protein and sugar that are the building blocks of cartilage.

Rheumatoid arthritis: A major form of the disease in which the body's immune system attacks joints, causing hot, painful swelling and deformity.